Method of prerecording tape and apparatus for use therewith

ABSTRACT

A method of recording a stereo audio tape having a pair of stereo tracks on each side with a monaural signal of sequence dependent information, and a tape produced thereby. The sequence dependent information is divided into four quarters with the first and second quarters being recorded onto one stereo channel on the two sides of the tape, and the third and fourth quarters being recorded on the other stereo channel on the two sides of the tape. The entire monaural recording is replayed by adjusting the balance control only once during the course of replaying the tape. An adaptor device is provided to adapt stereo systems without balance controls to the replaying of the prerecorded tape.

This is a continuation of application Ser. No. 667,642, filed Nov. 2,1984, now U.S. Pat. No. 4,855,844.

BACKGROUND OF THE INVENTION

The present application relates to the prerecording of audio tape, andin particular to a method of prerecording sequence dependent informationonto an audio tape monaurally, as well as an apparatus for usetherewith.

Various magnetic audio recording tapes and tape cassettes areconventionally known in the art. Typically, such audio tapes are usedwith a stereophonic tape recording and playing device in order toproduce a multi-track tape that reproduces stereophonic sound. Normally,such conventional stereo tape recording and replay equipment include areel mechanism that advances the tape past a split pick-up head. Thepick-up head simultaneously reads two adjacent magnetic tracks ofencoded information on the tape, each track corresponding to one channelof the stereophonic signal. Since the pick-up head either simultaneouslyrecords or replays the two adjacent tracks, complementary signals areencoded on each track or channel so as to be harmoniously mixed duringreplaying of the tape. Normally, the audio tape includes two pair orfour separate recording tracks. This allows the tape to be played ineach direction, with two adjacent tracks being dedicated to the twostereo channels in each direction.

Most conventional audio tape players utilize one of two methods toselect the direction of tape play or advancement and the particular pairof tracks to be played. In one class of tape playing devices the splitpick-up head maintains a single orientation. The tape is sufficientlywide that when the tape is loaded into the playing device only two ofthe tracks adjacent one edge of the tape are accessed by the pick-uphead. In order to change the tracks to be played the tape must bemanually removed from the player unit, turned over and reinserted forplay in the opposite direction. In the second class of tape playingdevices, the pick-up head itself is rotated and shifted within thedevice so as to be inverted and access the unplayed pair of tracks. Thedirection of tape travel or advancement within the device is alsoreversed.

Heretofore magnetic audio tapes have been prerecorded with two monauralsignals on two adjacent tracks in the same direction. Such prerecordedtapes find use in certain specific applications, for example, in foreignlanguage instruction and the like. The English material or questions arerecorded on one track separated by silent pauses, while the foreignlanguage counterpart is recorded on the second track at the locationscorresponding to the pauses. With such a prerecorded tape the user maylisten to the tape in a conventional fashion to hear the English phrasefollowed immediately by the foreign language counterpart. However, theuser may also operate the balance control of the stereo tape player inorder to select a single track or channel to be played. By setting thebalance to produce a maximum volume on one channel and a minimum volumeon the other, the student can select either the English phrase or theforeign language counterpart only to be replayed

In other applications conventional stereo audio tapes have been recordedwith monaural information on the adjacent tracks normally used to recordstereophonic information. For example, verbal material has been recordedon one track, such as a foreign language, while background sounds ormusic relating to the verbal material is recorded on the second track.The two tracks can therefore be replayed simultaneously with thebackground sounds complementing the spoken information. Stereophonicaudio tapes have also been prerecorded with background music on fourseparate tracks to be used in the replaying of monaural background musicin stores and the like.

Heretofore, however, there has not been available a method ofprerecording audio tapes that substantially increases the storagecapacity of the tape with sequence dependent or serialized informationand which also permits the replaying of the entire tape with a minimalamount of control adjustment.

SUMMARY OF THE INVENTION

The present invention provides for the storage on a prerecorded audiotape a relatively lengthy amount of sequence dependent or serializedinformation that is not required to be replayed stereophonically.Further, the invention provides for a method and apparatus for usetherewith that permits the replaying of such a prerecorded tape with aminimal number of tape player control adjustments.

The method includes dividing the continuously running, sequencedependent information, such as colloquy, drama or the like into fourconsecutive quarters. The information is prerecorded onto four tracks ofthe tape so that the first quarter is recorded in one direction on thetrack corresponding to the first stereo channel. The second quarter isrecorded in the reverse direction on the same stereo channel, so thatthe first quarter proceeds into the second quarter serially without achange in the stereo player balance control or the like. The thirdquarter is recorded in the original direction on the track correspondingto the second stereo channel, while the fourth quarter is recorded inthe reverse direction on the same stereo channel. The third quartertherefore proceeds serially into the fourth quarter without a change inthe balance control. When replaying the prerecorded audio tape, theentire tape may therefore be replayed with only a single change instereo channel selection after the second quarter has been completed.

Additionally, the method preferably includes spacing the tracks ofprerecorded material across the tape width in order to provide guardbands between adjacent tracks that reduce spurious signals or cross-talkfrom adjacent tracks. These guard bands are preferably encoded with amasking signal to further reduce spurious signals from adjacent tracks.

The invention also provides an adapter device that introduces a stereochannel or track selection control into a conventional stereo tapeplayer device. The adapter device mates with a conventional stereo tapeplayer output and speaker assembly input, and includes a switchingcircuit that selectively applies only one stereo channel from the stereotape player device to the speakers.

Although audio stereo tapes have previously been monaurally prerecordedon the various tracks, such tapes have not been prerecorded withsequence dependent information. Such tapes have been recorded with shortphrases, compilations of music and the like so that the sequence ofreply of the material is not important to its understanding. For thisreason these methods of prerecording the tape do not accommodate thesequential replay of all of the information on the tape without anincreased number of control adjustments and/or rewinding of the tape. Incontradistinction the present method provides for serialized replay ofall of the information on the tape with a minimum number of controladjustments and without rewinding the tape.

These and other features, objects and advantages of the invention willbe recognized by one skilled in the art from the written disclosurewhich follows and the drawings referenced herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary, schematic view of a magnetic audio tapeprerecorded according to the method of the present invention;

FIG. 2 is a perspective view of a stereophonic tape player and headphonespeaker system shown in combination with an adapter device embodying thepresent invention;

FIG. 3 is a fragmentary, plan view of the adapter of FIG. 2;

FIG. 4 is an end view of the adapter device shown in FIG. 3; and

FIG. 5 is a schematic circuit diagram of the adapter device shown inFIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the invention is shown in FIG. 1 as aprerecorded, magnetic audio tape referenced generally by the numeral 10.Tape 10 includes four tracks 12, 14, 16 and 18 on which are prerecordedsequentially dependent or serialized information. Each track ismonaurally prerecorded, so that the adjacent tracks do not containcomplementary audio material such as is found in a stereophonicrecording. Since tracks 12-18 contain noncomplementary information, thetracks are spaced by guard bands 20 which reduce spurious signals fromadjacent tracks during replay. Both during the prerecording of tape 10and during the replay thereof, tape 10 is used with conventionalstereophonic recording or playing equipment. The balance control of thestereo equipment is adjusted such that only a single track is encoded orplayed at a time. Tracks 12-18 are prerecorded in a specific sequencedescribed below such that the entirety of the material prerecorded onall four tracks may be replayed with only a single adjustment of thebalance control or stereo channel selection of the stereo equipment.

As shown in a preferred embodiment of FIGS. 2 and 3, a stereo adapter orconverter device is referenced generally by the numeral 24. As shown inFIG. 2, adapter 24 connects to a conventional stereo tape player 30 andspeaker system 32. Adapter 24 is preferably used to adapt a tape player30 without a balance control to the replaying of tape 10 prerecordedaccording to the method disclosed herein. Adapter 24 is also utilizedwith conventional stereo tape players having balance controls to providean alternate, quick and readily accessible adjustment control thatobviates the need for adjustment of the tape player's balance control.

More specifically, in reference to FIG. 1, tracks 12-18 are spacedacross the width of tape 10 so as to correspond to the location of aconventional split pick-up head (not shown) on a stereo tape recorder orplayer. Tracks 12-18 are grouped into two pairs of tracks, each paircorresponding to the two channels of a conventional stereophonic taperecorder or player. One pair of adjacent tracks, tracks 12 and 14, arelocated on tape 10 so as to correspond to the location of the splitpick-up head when tape 10 is advanced through the tape recorder orplayer device in a direction indicated by arrows "A". The other pair ofadjacent tracks, tracks 16 and 18, are located on tape 10 so as tocorrespond to the location of the split pick-up head when tape 10 isadvanced in a direction indicated by arrows "B". Due to the manner inwhich tape play direction is reversed in conventional tape playerdevices, the outermost tracks, 12 and 18 correspond to one stereophonicchannel, while the two inner tracks 14 and 16 correspond to the otherstereophonic channel. This permits the direction of advancement of tape10 to be reversed simply by removing tape 10 from the tape player,inverting tape 10 and reinserting tape 10 in the tape player.Alternatively, conventional automatically reversing stereo tape playersphysically rotate the split pick-up head 180 degrees, and thereforeaccess the same pattern of tracks 12-18.

Sequence dependent information is monaurally recorded upon tracks 12-18.Sequence dependent or serialized information refers to colloquy, dramaor the like. Exemplary of such sequence dependent information is thereading or dramatization of literary works. Sequence dependentinformation is characterized by its dependence upon consecutiverendition in order to be understandable, unlike compilations ofunrelated music, songs, foreign language phrases or the like.

The sequence dependent information to be recorded is divided into fourconsecutive quarters or portions. These four quarters are prerecordedonto tape 10 so as to proceed in a logical fashion from the beginning ofthe information on the first quarter to the termination at the end ofthe fourth quarter. When recorded according to the method discussedbelow, a prerecorded tape 10 results having the first quarter portion ofmaterial prerecorded onto track 12 in direction of advancement "A" tothe end of tape 10. The second quarter portion of information isprerecorded on track 18 in direction "B", so that both the first andsecond quarter portions are recorded at locations corresponding to thesame stereophonic channel. The third quarter portion is prerecorded ontrack 14 in direction "A". The final quarter portion is prerecorded ontrack 16 in direction "B", so that the third and final quarter portionsare both recorded at locations corresponding to the other stereophonicchannel. The sequence for logical replay of tape 10 is therefore tracks12, 18, 14 and 16.

Tape 10 is prerecorded in the above sequence with the use ofconventional audio tape recording equipment (not shown). Tape 10 ispreferably mounted on a conventional audio tape cassette 34 (FIG. 2) andplaced within the recording device. Tape 10 is advanced through therecording device in direction "A" while the balance control of therecording device is adjusted so that the first quarter portion ofinformation is only recorded onto track 12. The direction of advance oftape 10 is then reversed, either by physically removing tape 10 from therecording device and inverting the tape or alternatively, by rotatingthe orientation of the split pick-up head. Tape 10 is advanced throughthe recording device in direction "B" while the balance control remainsunchanged so that the second quarter portion is recorded onto track 18.The direction of advance of tape 10 is again reversed and the balancecontrol is adjusted so that the other of the two stereophonic channelsis selected. Tape 10 is advanced through the recording device indirection "A" while the third quarter portion is recorded on track 14.The direction of advance of tape 10 is reversed a final time todirection "B", and the balance control is unchanged to prerecord thefinal quarter portion onto track 16. The entirety of the sequencedependent information is therefore prerecorded onto tape 10 withoutnecessitating the rewinding of the tape and with the requirement of onlya single adjustment of the balance control.

Alternatively, if tracks 14 and 16 are designated as corresponding tothe first stereo channel, rather than tracks 12 and 18, the sequence ofrecording and replaying tracks 12-18 is changed, but the method ofrecording and replaying tape 10 is not changed thereby. The first stereochannel is selected and tape 10 is recorded in the two directions on thetwo "sides" of tape 10. The other one of the stereo channels is thenselected and tape 10 is recorded in the two directions on the two"sides" of tape 10. When tracks 14 and 16 are designated as the firststereo channel the sequence of logical replay of tape 10 is track 14,16, 12 and 18.

It will be noted that adjacent tracks 12-18 of tape 10 are prerecordedwith noncomplementary subject matter. Therefore, any overlap of the tapereading element onto adjacent tracks will cause interference with orcross-talk on the particular track being replayed. Such cross-talk mayoccur as tape 10 shifts slightly during advancement through the tapeplaying device, or from strong signals being recorded on adjacent tracksor the like. Tape 10 therefore includes guard bands 20 which separateadjacent tracks 12-18. Guard bands 20 space tracks 12-18 sufficiently sothat overlapping of adjacent tracks on the split pick-up head isprevented and thus stray signals are avoided. Preferably guard bands 20are blank sections of tape, although in alternative preferredembodiments, guard bands 20 include a masking signal encoded thereon.

The masking signals recorded on guard bands 20 either prevent orameliorate the stray signals between adjacent tracks 12-18. Theparticular masking signal may comprise a variety of alternative signals.One alternative masking signal is a combination of all audiblefrequencies, commonly referred to as white noise. Another alternativemasking signal is a signal of low amplitude and constant or varyingfrequency, commonly referred to as small noise. Another alternativemasking signal is a bias current of a high, unaudible frequency, rangingas high as one hundred thousand hertz. Still another alternative maskingsignal is music or other complementary sounds associated with theprogram information on the track being replayed. With such complementarysounds each guard band 20 may be split into two half bands, with themasking signal being prerecorded in different directions on each halfband. With any of the above masking signals, the masking signal may beprerecorded onto guard bands 20 during the prerecording of tracks 12˜18,or alternatively may be prerecorded either before or after theprerecording of tracks 14-18.

Shown in FIG. 2, tape player 30 is of conventional audio tape cassetteplaying design but does not include a balance control. Adapter 24includes a conventional male 3.5 millimeter stereo plug 50 having twoelectrical leads 52 and 54 that telescopingly mate with a conventionalstereo output jack. Plug 50 is connected by a two wire cable 56 to acylindrically shaped switch 58. Opening axially inward of the end ofswitch 58 opposite cable 56 is a conventional 3.5 millimeter stereo jack60. Stereo jack 60 includes electrical leads 62 and 64 (FIG. 5) thattelescopingly mate with a conventional stereo plug. Speaker system 32 asshown in FIG. 2 is implemented as a headset system of conventionaldesign. Speaker system 32 includes a conventional male 3.5 millimeterstereo plug 70 connected by a two wire cable 72 to a pair of headbandmounted speakers 74. When assembled, plug 50 on adapter 24 istelescopingly received in the outlet of tape player 30, while plug 70 onspeaker system 32 is telescopingly received in jack 60.

As shown schematically in FIG. 5, the circuit of adapter 24 includesgrounded male plug 50 with leads 52 and 54. Leads 52 and 54 are bothconnected to switch 58, which is a two position, double pole, doublethrow switch. In the preferred embodiment shown in FIG. 3, switch 58 isimplemented with a slide switch. As shown in the schematic of FIG. 5,switch 58 includes a pair of input terminals 80 and 82 that areconnected to leads 52 and 54 respectively. On either side of switch 58an outlet terminal 84, 86 is applied through a resistor 88 to ground. Oneither side of switch 58 the remaining outlet terminals 90, 92 are bothconnected through a single lead to a resistor 94, which is applied toboth outlet leads 62 and 64 of jack 60.

In operation, switch 58 applies the signal from one of plug leads 52 and54 to both outlet leads 60 and 64, while the signal from the other ofplug leads 52, 54 is applied to resistor 88. Preferably resistor 88ranges between eight and sixty-five Ohms at one-quarter watt or less.Resistor 94 ranges between zero to thirty Ohms at one-quarter watt orless.

In order to review the entire tape with adapter 24 connected to tapeplayer 30 and speaker system 32, the operator is only required to firstadvance both sides of tape 10 through the player with switch 58 set toselect the first stereo channel. Switch 58 is then adjusted to selectthe second stereo channel and both sides of tape 10 are again advancedthrough player 30. If tape player 30 is provided with an automaticreverse play function, all that is required is to adjust switch 58 onceafter both sides of tape 10 have been sequentially played one time.

It is to be understood that the above is merely a description of thepreferred embodiment, and one skilled in the art will recognize thatvarious modifications or improvements may be made without departing fromthe spirit of the invention disclosed therein. The scope of theprotection afforded is to be determined by the claims which follow andthe breadth of protection that the law allows.

The embodiments of the invention in which an exclusive property orprivilege is claimed are as follows.
 1. A method of recording aconventional, stereo audio cassette tape of the type having first andsecond sides, and a pair of stereo tracks on each side, withcontinuously running, sequence dependent information, in combinationwith a method of playing said tape with a conventional stereophonicaudio tape player of the type having a stereophonic pick-up head withfirst and second channels, and a balance control to vary the relativeoutput volume of said first and second channels; said methodcomprising:providing sequence dependent information comprising a singleliterary work; dividing said literary work into four, consecutiveportions, comprising a first quarter, a second quarter, a third quarterand a fourth quarter; audibly rendering said first quarter of saidliterary work and recording said first quarter onto one of the stereotracks on the first side of said tape in a first direction, at alocation along the width of said tape corresponding to said firstchannel of said stereophonic pick-up head when said tape is oriented toplay the first side thereof; audibly rendering said second quarter ofsaid literary work and recording said second quarter onto one of thestereo tracks on the second side of said tape in a second directionopposite to said first direction, at a location along the width of saidtape corresponding to said first channel of said stereophonic pick-uphead when said cassette tape is oriented to play the second sidethereof; audibly rendering said third quarter of said literary work andrecording said third quarter onto the other of the stereo tracks on thefirst side of said tape in said first direction, at a location along thewidth of said tape corresponding to said second channel of saidstereophonic pick-up head when said cassette tape is oriented to playthe first side thereof; audibly rendering said fourth quarter of saidliterary work and recording said fourth quarter onto the other of thestereo tracks on the second side of said tape in said second direction,at a location along the width of said tape corresponding to said secondchannel of said stereophonic pick-up head when said cassette tape isoriented to play the second side thereof; inserting said cassette tapein said tape player in an operational orientation to play the first sideof said cassette tape; adjusting said balance control for maximum outputvolume of said first channel and minimum output volume of said secondchannel; playing the first quarter of said literary work to the end ofsaid one stereo track on the first side of said tape; ejecting saidcassette tape from said tape player, reversing the orientation of saidcassette tape with respect to said tape player and reinserting saidcassette tape in said tape player in an operational orientation to playthe second side of said tape; playing the second quarter of saidliterary work to the end of said one stereo track on the second side ofsaid tape; ejecting said cassette tape from said tape player, reversingthe orientation of said cassette tape with respect to said tape playerand reinserting said cassette tape in said tape player in an operationalorientation to again play the first side of said tape; adjusting saidbalance control for minimum output volume of said first channel andmaximum output volume of said second channel; playing the third quarterof said literary work to the end of said other stereo track on the firstside of said tape; ejecting said cassette tape from said tape player,reversing the orientation of said cassette tape with respect to saidtape player, and reinserting said cassette tape in said tape player inan operational orientation to again play the second side of said tape;playing the fourth quarter of said literary work to the end of saidother stereo track on the second side of said tape, whereby said entiretape is played in proper sequence with only a single adjustment of saidbalance control; said recording steps include spacing said stereo tracksacross said tape to provide a spacing band between adjacent ones of saidstereo tracks; and encoding a masking signal on said tape at saidspacing bands.
 2. The method of claim 1, wherein:said masking signalcomprises a high bias frequency signal.
 3. The method of claim 1,wherein:said masking signal comprises all audible frequencies.
 4. Themethod of claim 1, wherein:said masking signal comprises a signal havingan amplitude substantially less than the amplitude of said informationrecorded on said stereo tracks.
 5. The method of claim 1, wherein:saidmasking signal comprises music associated with the sequence dependentinformation recorded on said stereo tracks.